CN1056176A - The resonance tracking system of sound suspending device - Google Patents
The resonance tracking system of sound suspending device Download PDFInfo
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- CN1056176A CN1056176A CN 91103537 CN91103537A CN1056176A CN 1056176 A CN1056176 A CN 1056176A CN 91103537 CN91103537 CN 91103537 CN 91103537 A CN91103537 A CN 91103537A CN 1056176 A CN1056176 A CN 1056176A
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Abstract
The resonance tracking system of sound suspending device has the resonance chamber 1 between transducer 2 and the reflecting surface 3, an input end of binary channels lock-in amplifier 6 links to each other with signal generator 4, another input end links to each other with reflecting surface 3 by microphone amplifier 5, and the lock-in amplifier output terminal links to each other with reflecting surface 3 with topworks 8 by regulator 7; By processing to phase signal, can adjust the long or frequency in chamber of resonance chamber, make system keep the optimum resonance condition.
Description
The invention belongs to the electric variable regulating system.
Using acoustic levitation technique can and be positioned in the fluid media (medium) of chamber solid particle or drop suspension, does not need to support suspended matter with support or container.This is in microgravity condition, even in earth gravity field, carry out no container and process, the preparation high-purity material has been created an advantageous environment, also be applied to gradually simultaneously in the research of heterogeneous phase chemical reaction process of condensed phase reaction system, the common sound suspending device that adopts all is to form enough strong resonance standing-wave sound field between the sound source of suspension chamber and reflecting surface, and suspended matter is suspended on the acoustic pressure node of appointment.Reach resonance when chamber length L satisfies L=n λ/2=n/2 c/f during condition, n is the acoustic pressure node number in the chamber in the formula, promptly possible levitation position number; F is the vibration frequency of sound source; C and λ are the phase velocity and the wavelength of the pattern sound wave of setting up in the chamber.The phase velocity c of certain pattern sound wave is proportional to the velocity of sound Co of free travelling wave under the same terms in the chamber, and the latter is then by medium state decision in the chamber.In the application of the acoustic levitation technique that exemplifies in the above, usually need suspended matter and medium are heated or cool off, the composition of medium also can change when suspension reacts simultaneously.These all can cause the variation of the velocity of sound, thereby destroy original condition of resonance in the chamber.Therefore in the suspension process, the constantly influence of the variation of factors such as medium temperature, composition, pressure in the compensated cavity is followed the tracks of and is set up the new condition of shaking of wiping, and keeps the condition precedent of stable suspersion exactly, that is the task of resonance tracking system.Shake condition formula as can be known by above-mentioned wiping, and when the state of chamber inner fluid medium is restricted by the suspended matter chemical reaction process, in the time of can not changing arbitrarily, for vibration mode certain in the chamber (n fixes), condition of resonance is by long λ in chamber and frequency of source f decision.The sound suspending device of under the earth gravity field environment, setting up owing to must in the chamber, excite very strong sound field, usually without loudspeaker, and with piezoelectric transducer as sound source.Because the latter can not change frequency in the scope of broad, therefore, can only adopt the long method in chamber of regulating.A key issue in the resonance tracking system design is to select a suitable variable as the Be Controlled variable.When chamber reached resonance, the acoustic pressure of reflecting surface reached maximum value, and the electric current that flows through transducer also should reach maximum value.Therefore prior art makes the reflecting surface acoustic pressure or reaches maximum value by transducer current by regulating chamber length or frequency mostly, thereby sets up and the maintenance condition of resonance.But because this extreme value is not a definite numerical value, with transducer power, factors such as temperature and changing, therefore can not adopt common fixed set point control system, and the need extremum control system, promptly constantly add a little disturbance to control variable, from definite direction and the size of regulating of the variation of Be Controlled variable, search is long or frequency corresponding to the chamber of control variable maximum value.This makes the design of regulator complicated, and the Be Controlled variable always is among the little fluctuation variation simultaneously.Therefore select a kind of new control method, condition of resonance is set up in tracking in the acoustic levitation chamber very big using value.See United States Patent (USP) 4463606.
The objective of the invention is to make the phase differential of suspension chamber input and output signal to remain on an optimum value, thereby keep the condition of resonance of chamber automatically.
Principal feature of the present invention is that the resonance tracking system of sound suspending device has the resonance chamber 1 between transducer 2 and the reflecting surface 3, be used for solid particle or drop are suspended on the acoustic pressure node of the appointment in the fluid media (medium) resonance stationary field in the resonance chamber 1, suspended matter is heated by laser or the outer heating element of chamber wall by the window on the chamber wall, an input end of binary channels lock-in amplifier 6 links to each other with signal generator 4, another input end links to each other with reflecting surface 3 by microphone amplifier 5, the output terminal of lock-in amplifier 6 links to each other with reflecting surface 3 with topworks 8 by regulator 7, said binary channels lock-in amplifier 6 is added in voltage on the ultrasonic transducer 2 with signal generator 4 respectively and the acoustic pressure on the reflecting surface 3 is its reference and detected input signals, the deviation of its phase place output signal the two phase differential when two phase of input signals differences lock relatively for this reason, the deviation signal of 7 pairs of inputs of said regulator is handled the back and is produced control signal, adjust the position of reflecting surface 3 by topworks 8, making deviation is zero, chamber remains under the optimum resonance condition, and suspended matter is kept stable suspersion; An input end of said lock-in amplifier 6 links to each other with power amplifier 10, another input end links to each other with reflecting surface 3 by microphone amplifier 5, the output terminal of lock-in amplifier is by regulator 7 and voltage controlled oscillator 9, power amplifier 10 is linked on the transducer 2, binary channels lock-in amplifier 6 is added in voltage on the ultrasonic transducer 2 with power amplifier 10 respectively and the acoustic pressure on the reflecting surface 3 is its reference and detected input signals, its phase place output signal for this reason two input signal phase differences with respect to the deviation of the two phase differential of when locking, the deviation signal of 7 pairs of inputs of regulator is handled the back and is produced control signal, act on the said voltage controlled oscillator 9, this signal is after power amplifier 10 amplifies, adjust the vibration frequency of transducer 2, making deviation is zero, chamber remains under the optimum resonance condition, and suspended matter is kept stable suspersion.
The present invention as controlled variable, is the set-point of controlled volume with the phase differential of condition of resonance lower chambers input and output signal with the phase differential of suspension chamber input and output signal, constitutes the closed loop constant value control system.Therefore the influence that the chamber inner fluid medium state that suspends changes can be compensated automatically by regulating the long or frequency of source in chamber, keeps the condition of resonance in the chamber, guarantees the stable suspersion of object.
Fig. 1 is the resonance tracking system synoptic diagram of the single shaft sound suspending device of accommodation reflex face position.1 is the suspension chamber among the figure, and 2 is transducer, and 3 is reflecting surface, and 4 is signal generator, and 5 is sound pressure sensor and microphone amplifier; 6 is lock-in amplifier, and 7 is regulator, and 8 is topworks.
Fig. 2 is the resonance tracking system synoptic diagram of the single shaft sound suspending device of adjusting sound source vibration frequency.9 is voltage controlled oscillator among the figure, and 10 is power amplifier,
Discuss the present invention in detail below by accompanying drawing.Fig. 1 is illustrated in the single shaft sound suspending device, by regulating the long control system that realizes that resonance is followed the tracks of in chamber.One end of suspension chamber is a sound source 2, and the other end is a reflecting surface 3, and solid particle or drop can be suspended in the acoustic pressure node place of appointment in the standing-wave sound field.Be provided with the window of some on the chamber wall over against levitation position,, utilize laser energy heating suspended matter for adding and taking out suspended matter, with the surface temperature of infrared radiation temperature measurement device mensuration suspended matter, and the variation of observation and record suspended matter form and size etc.Heating to suspended matter also can realize by the electrical heating elements outside chamber.The sound source of this class levitation device adopts power big more, but the very narrow transducer of fixed-frequency or frequency range, for example piezoelectric transducer.Electric current by transducer and be added in that signal voltage can be monitored by dual channel oscilloscope on the transducer.The sound source radiation face can pass through mechanical hook-up with respect to position of window, and manual adjustments is to guarantee that suspended matter is all the time over against window in the suspension process.A microphone amplifier 5 is installed on the reflecting surface, and reflecting surface 3 positions are controlled by resonance tracking system, also can manual adjustments.The core of resonance tracking system is a lock-in amplifier 6, the voltage signal that from the output circuit of signal generating system, takes out, through behind the filter shape as the reference signal of lock-in amplifier 6.Microphone amplifier 5 converts the acoustic pressure of reflecting surface 3 to voltage signal, delivers to microphone amplifier 5, by the Displaying Meter of microphone amplifier 5, can understand the variation of reflecting surface sound pressure level.The output of microphone amplifier 5 simultaneously is input to lock-in amplifier 6 as measured signal.Adjust the sensitivity and the phase place of lock-in amplifier 6, realize the locking of reference channel.Reference channel is in case locking, and the output of the phase place of lock-in amplifier 6 promptly is the reference signal and the measured signal of lock-in amplifier 6, that is the deviation of suspension chamber input and output signal phase differential the two phase differential during with respect to locking.There are 90 ° of phase differential in typical vector piece one-spring forced vibration system between the displacement of vector piece and the driving force when reaching resonance, in fact this also is the ultimate principle of resonance tracking system of the present invention.Be because the signal process is changed, filtering, processing such as shaping, the phase differential of chamber input and output signal is not necessarily 90 ° during resonance, still, is a definite value.Concrete regulating step is as follows: under the condition of the certain power input of ultrasonic vibration system, it is long manually to regulate the chamber earlier, sets up the condition of resonance of suspension chamber.The reflecting surface sound pressure level that the foundation of condition of resonance can be shown by microphone amplifier, or the waveform of the transducer input signal that shows of oscillograph determines mainly reaches the stable suspersion reflection by chamber inner suspension body.Manually or automatically regulate the sensitivity and the phase place of lock-in amplifier 6, realize the locking of reference channel, with the phase differential between this moment lock-in amplifier 6 references and measured signal as benchmark.After this in the suspension process, when suspension chamber off-resonance condition, lock-in amplifier 6 phase place output signals are exactly the deviation of this phase deviation under suspension chamber input and output signal phase differential and the condition of resonance, the regulator 7 of resonance tracking system, size and Orientation according to this input deviation signal, determine the size and Orientation of the control signal of output by certain control law, change the position of reflecting surface by topworks, the adjusting chamber is long, phase differential deviation up to suspension chamber input and output signal is zero, sets up new condition of resonance.
Fig. 2 is illustrated in the same sound suspending device, by regulating the control system that frequency of source realizes that resonance is followed the tracks of, be in certain input power range with the difference of application example shown in Figure 1, frequency of source can be regulated in the scope of broad continuously, for example adopt powerful dynamic loudspeaker, and the position of sound source and reflecting surface, or the chamber of floater length then immobilizes.Resonance tracking system is still the deviation decision control signal according to the suspension chamber input and output signal phase differential of lock-in amplifier 6 outputs, by regulating frequency of source, sets up new condition of resonance.Therefore difference only is controller, should use the example middle controller to deviation signal from lock-in amplifier 6, handle by certain control law, the control signal of output acts on the voltage controlled oscillator 9 of signal generating system, by power device 10 signal being amplified the vibration frequency that the back changes loudspeaker, is zero until the deviation of suspension chamber input and output signal phase differential.
Claims (5)
1; the resonance tracking system of sound suspending device has the resonance chamber 1 between transducer 2 and the reflecting surface 3; be used for solid particle or drop are suspended on the acoustic pressure node of the appointment in the fluid media (medium) resonance stationary field in the resonance chamber 1; suspended matter is heated by laser or the outer heating element of chamber wall by the window on the chamber wall; an input end that it is characterized by binary channels lock-in amplifier 6 links to each other with signal generator 4; another input end links to each other with reflecting surface 3 by microphone amplifier 5; the lock-in amplifier output terminal links to each other with reflecting surface 3 with topworks 8 by regulator 7; said binary channels lock-in amplifier 6 is added in voltage on the ultrasonic transducer 2 with signal generator 4 respectively and the acoustic pressure on the reflecting surface 3 is its reference and detected input signals; its phase place output signal for this reason two input signal phase differences with respect to the deviation of the two phase differential of when locking; the deviation signal of 7 pairs of inputs of said regulator is handled the back and is produced control signal; adjust the position of reflecting surface 3 by topworks 8; making deviation is zero; chamber remains under the optimum resonance condition, and suspended matter is kept stable suspersion.
2, it is characterized by the binary channels lock-in amplifier by the resonance tracking system of the described sound suspending device of claim 1 is lock-in amplifier.
3, it is characterized by transducer 2 by the resonance tracking system of the described sound suspending device of claim 1 and be loudspeaker or piezoelectric transducer.
4, it is characterized by regulator 7 by the resonance tracking system of the described sound suspending device of claim 1 and be the negative feedback regulator.
5, the resonance tracking system of sound suspending device has the resonance chamber 1 between transducer 2 and the reflecting surface 3, be used for solid particle or drop are suspended on the acoustic pressure node of appointment in the fluid media (medium) resonance stationary field in the resonance chamber 1, suspended matter is heated by laser or the outer heating element of chamber wall by the window on the chamber wall, an input end that it is characterized by binary channels lock-in amplifier 6 links to each other with power amplifier 10, another input end links to each other with reflecting surface 3 by microphone amplifier 5, the output terminal of lock-in amplifier is by regulator 7 and voltage controlled oscillator 9, and power amplifier 10 is linked on the transducer 2; Said binary channels lock-in amplifier 6 is added in voltage on the ultrasonic transducer 2 with power amplifier 10 respectively and the acoustic pressure on the reflecting surface 3 is its reference and detected input signals, its phase place output signal for this reason two input signal phase differences with respect to the deviation of the two phase differential of when locking, the deviation signal of 7 pairs of inputs of regulator is handled the back and is produced control signal, act on the said voltage controlled oscillator 9, this signal is after power amplifier 10 amplifies, adjust the vibration frequency of transducer 2, making deviation is zero, chamber remains under the optimum resonance condition, and suspended matter is kept stable suspersion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 91103537 CN1023873C (en) | 1991-05-31 | 1991-05-31 | Resonance tracking system of sound suspending device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 91103537 CN1023873C (en) | 1991-05-31 | 1991-05-31 | Resonance tracking system of sound suspending device |
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| Publication Number | Publication Date |
|---|---|
| CN1056176A true CN1056176A (en) | 1991-11-13 |
| CN1023873C CN1023873C (en) | 1994-02-23 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 91103537 Expired - Fee Related CN1023873C (en) | 1991-05-31 | 1991-05-31 | Resonance tracking system of sound suspending device |
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| CN (1) | CN1023873C (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102527488A (en) * | 2011-12-27 | 2012-07-04 | 中国矿业大学 | Ultrasonic separating device for micro-nano particles |
| CN104259081A (en) * | 2014-07-30 | 2015-01-07 | 南京航空航天大学 | Frequency tracking method of piezoelectric transducer and frequency tracking system thereof |
| CN105575231A (en) * | 2015-12-18 | 2016-05-11 | 中山市民众镇民众中心小学 | Acoustic levitation demonstrator |
| CN107202812A (en) * | 2016-09-08 | 2017-09-26 | 江苏科技大学 | A kind of many drop evaporations of acoustic levitation and combustion experimental device and its method |
| CN107431853A (en) * | 2015-02-13 | 2017-12-01 | 凯奥福德股份公司 | Loudspeaker enclosure with sealed acoustic suspension chamber |
| CN107680455A (en) * | 2017-08-28 | 2018-02-09 | 西北工业大学 | Using the ultrasound suspending device and experimental method of super-hydrophobic reflection end loading water droplet |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102006053112A1 (en) * | 2006-11-10 | 2008-05-15 | Robert Bosch Gmbh | Method for controlling a transmission sound pressure and a reception gain of a sensor |
-
1991
- 1991-05-31 CN CN 91103537 patent/CN1023873C/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102527488A (en) * | 2011-12-27 | 2012-07-04 | 中国矿业大学 | Ultrasonic separating device for micro-nano particles |
| CN104259081A (en) * | 2014-07-30 | 2015-01-07 | 南京航空航天大学 | Frequency tracking method of piezoelectric transducer and frequency tracking system thereof |
| CN107431853A (en) * | 2015-02-13 | 2017-12-01 | 凯奥福德股份公司 | Loudspeaker enclosure with sealed acoustic suspension chamber |
| CN105575231A (en) * | 2015-12-18 | 2016-05-11 | 中山市民众镇民众中心小学 | Acoustic levitation demonstrator |
| CN105575231B (en) * | 2015-12-18 | 2018-06-26 | 关朋伟 | A kind of acoustic levitation demonstration device |
| CN107202812A (en) * | 2016-09-08 | 2017-09-26 | 江苏科技大学 | A kind of many drop evaporations of acoustic levitation and combustion experimental device and its method |
| CN107680455A (en) * | 2017-08-28 | 2018-02-09 | 西北工业大学 | Using the ultrasound suspending device and experimental method of super-hydrophobic reflection end loading water droplet |
| CN107680455B (en) * | 2017-08-28 | 2020-02-14 | 西北工业大学 | Ultrasonic suspension device adopting super-hydrophobic reflection end to load water drops and experimental method |
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| Publication number | Publication date |
|---|---|
| CN1023873C (en) | 1994-02-23 |
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